\begin{tikzpicture}
    \tkzDefPoints{0/0/B, 3/0/C}
    \tkzDefTriangle[equilateral](B,C)  \tkzGetPoint{A}

    \tkzDrawPolygon(A,B,C)
    \tkzMarkSegments[mark=|](A,B  A,C  B,C)
    \tkzLabelPoints[above](A)
    \tkzLabelPoints[below](B,C)
\end{tikzpicture}

